Mounting arrangement for a resonant spring in a linear motor compressor

ABSTRACT

The compressor of the invention comprises: a block with a cylinder; a movable assembly formed by a piston reciprocating in the cylinder and coupled to an actuating means by a rod; and a resonant spring having a first and a second diametrical end portion which are attached to the movable assembly by a first fixation means (MF 1 ) and, to the block, by a second fixation means (MF 2 ) which is adjustably attached to the block and to said second end portion so as to affix the latter to the block in a position defined along the displacement of the resonant spring in three directions orthogonal to one another and defined by the direction of the axis of the resonant spring, by the diametrical direction of the second end portion and by the diametrical direction orthogonal to said two first directions, and also along the angular displacement of said second end portion around said three directions orthogonal to each other.

FIELD OF THE INVENTION

The present invention refers to a mounting arrangement for a resonantspring in a compressor of the type driven by a linear motor and, moreparticularly, to a mounting arrangement for a resonant spring of thetype which couples a compression movable assembly, that is, apiston-rod-actuating means assembly, to a non-resonant assemblygenerally defined by a cylinder block affixed in the interior of acompressor shell.

PRIOR ART

As exemplarily illustrated in FIG. 1 of the enclosed drawings, thecompressors, generally used for refrigeration and driven by an electricmotor of the linear type, comprise a shell 1, generally hermetic andwhich houses a non-resonant assembly including a block 10 which can bemounted in the shell 1 by means of suspension springs 11, such as forexample, helical springs.

The block 10 incorporates a cylinder 12 in whose interior is defined acompression chamber 13, having an end 13 a generally closed by a valveplate 14 and by a head 25, and an open opposite end 13 b through whichis mounted a piston 20 reciprocating in the interior of the compressionchamber 13. The piston 20 is coupled, generally by means of a rod 30, toan actuating means 40 which carries magnets 41 energized by the linearmotor M which is mounted to the block 10.

The linear motor M is responsible for generating the necessary drive todisplace the piston 20 in the interior of the compression chamber 13 ofthe cylinder 12 and, consequently, for compressing the refrigerant fluidin the form of gas.

To the movable assembly, defined by the piston, the rod and theactuating means, is coupled a resonant spring 50 mounted in a manner toexert opposite axial forces on the piston 20, upon its reciprocatingaxial displacement in the interior of the compression chamber 13. Theresonant spring 50 operates as a guide for the axial displacement of thepiston 20, further actuating on the compression movable assemblytogether with the linear motor M of the compressor. The compressionmovable assembly and the resonant spring define the resonant assembly ofthe compressor.

In the prior art construction, exemplified in FIG. 1, the resonantspring 50 presents a helical shape having a first and a second endportion 50 a, 50 b that are defined by diametrically disposed springextensions, said end portions being respectively attached to thecompression movable assembly (generally to the actuating means 50) by afirst fixation means MF1 and, to the non-resonant assembly, for exampleto the block 10 or to the supporting structure thereof, by a secondfixation means MF2.

In this type of construction, as illustrated in FIG. 1 of the encloseddrawings, each first and second fixation means MF1, MF2 comprises a baseportion b1, b2, which is rigidly attached to the movable assembly and tothe non-resonant assembly, respectively, and a cover portion t1, t2 tobe screwed against the respective base portion b1, b2, for retaining,between said base portion b1, b2 and cover portion t1, t2, respectively,the first and the second end portion 50 a, 50 b of the resonant spring50. The base and cover portions are configured to define respectivesleeve portions defining concave cradles for the seating of thediametrical end portions 50 a, 50 b of the resonant spring 50. This typeof mounting arrangement presents some drawbacks, such as the possibilityof occurring gaps and the requirement of precise dimensioning, that is,with reduced manufacturing and mounting tolerances.

In the type of mounting arrangement illustrated in FIG. 1, it is notpossible to carry out a longitudinal dimensional adjustment of theresonant assembly, that is, of the distance between the top of thepiston 20 and the valve plate 14 during the mounting of the compressor.It is not also possible to carry out any rotational adjustment of theresonant assembly around the axis of the resonant spring 50. It is onlypossible, before the final tightening of the screws, to effect anadjustment by linearly and angularly displacing the end portions of theresonant spring 50, in the diametrical direction orthogonal to the axisof the spring and around the axis of said end portions 50 a of thespring 50.

Thus, in said prior art mounting arrangements, the dimensioning andmounting of the parts defined by the piston 20, the rod 30, theactuating means 40 and the resonant spring 50, are required to be madewith strict tolerances, which are of complex and expensive execution toguarantee two mounting conditions considered fundamental for the correctoperation of the compressor and which can be defined as follows:

-   -   firstly, the position of the top of the piston in relation to        the valve plate, in the mounting condition, for allowing the        piston to approximate, as much as possible, the valve plate in        the upper dead point condition, that is, in the compression        stroke end condition, in order to minimize the dead volume of        refrigerant gas in the interior of the compression chamber and,        thus, to minimize the efficiency losses of the compressor; and    -   secondly, the alignment of the piston in relation to the        cylinder, in order to minimize the loading on the bearing (oil        or pneumatic).

However, for obtaining the correct distance from the top of the pistonto the top of the cylinder, during the mounting process, there is achain of small tolerances to be maintained, so that the final toleranceof the mentioned distance remains within acceptable levels.

Moreover, for obtaining the correct alignment of the piston in relationto the cylinder, it is necessary to maintain the same low levels for thetolerances orthogonal to the main axis of the compressor. This implieshigh manufacturing costs for the involved components.

The piston 20 is coupled to the actuating means 40 so as to allow thetransfer of forces therebetween and the displacement of the piston 20,according to an axial direction coincident with the axis of thecompression chamber 13, so as to minimize the transversal reactionforces of the block 10 against the piston 20. Such transversal reactionforces of the block 10 against the piston 20 can provoke excessivefriction between the piston and the cylinder block, leading to: anincrease of energy consumption, with consequent reduction of theefficiency of the compressor; an accelerated wear of the componentssubject to greater friction levels, reducing the useful life of thecompressor; and the presence of noise due to the friction.

The problems mentioned above make desirable an arrangement for mountingthe parts defined by the piston, the rod, the actuating means and thecylinder block which guarantees, by means of component parts withrelatively larger manufacturing and assembly tolerances, the alignmentof the piston to the axis of the cylinder, as well as a correctpositioning of the top of the piston in relation to the valve plate, inthe mounting or stationary condition of the piston.

A solution for said difficulties in mounting the resonant spring in alinear compressor is proposed in the Brazilian Patent. Application PI07055541-2, of the present applicant.

According to said prior art solution, the resonant spring has a firstend portion affixed to the cylinder block of the compressor by a firstfixation means, and a second end portion affixed to a movable assemblydefined by the piston, the rod and the actuating means, by a secondfixation means.

In said previous construction, at least one of the first and secondfixation means comprises: a bearing portion previously affixed, by afirst side, around one of the end portions of the resonant spring andhaving, on an opposite side, a fixation face; and a bearing receivingportion previously attached, by one side, to one of the parts ofcylinder block and of movable assembly, and having, on an opposite side,a junction face. Said fixation and junction faces of the bearing portionand bearing receiving portion of the fixation means are seated and fusedto each other, so as to attach the respective end portion of the springto one of the parts of movable assembly and of cylinder block,maintaining said movable assembly concentric to the cylinder and in apredetermined axial positioning.

Although allowing, by means of a simple construction of low complexity,a correct positioning of the piston in the interior of the cylinder,without requiring small tolerances for the involved parts, this knownsolution presents the inconveniences of using plastic materials, to bethermally fused to each other and which present flexibility or elasticdeformation when subject to compression forces, allowing undueamplification of the forces actuating on the resonant spring andunbalances in the excitation of the latter.

Other inconvenience in using plastic material is the need of applyingespecial and costly materials to reduce the elasticity of the fixationmeans and maximize its resistance to aging by thermo-chemicaldeterioration. Even using especial plastics, this prior art solutionstill faces the issue of providing a reliable mounting arrangement forthe whole useful life of the compressor.

SUMMARY OF THE INVENTION

In view of the inconveniences mentioned above, the present invention hasthe generic object of providing a mounting arrangement for a resonantspring in a linear compressor, of the type considered above and whichallows using component parts with a relatively simple construction andassembly, without requiring very strict tolerances for obtaining acorrect centralized positioning of the piston in the interior of thecylinder and a resistant and reliable mounting arrangement for the wholeuseful life of the compressor, without interfering in the operationalcharacteristics of the resonant spring.

The present invention has also the object of providing a mountingarrangement, such as cited above and which is capable of guaranteeing,upon mounting the piston to the cylinder, a predetermined distancebetween the top of the piston and the valve plate, so as to guarantee anadequate volumetric capacity for the compressor.

Other object of the present invention is to guarantee a correctpositioning of the magnets (41) in relation to the motor (M) with anadequate concentricity in the two directions orthogonal to thedisplacement axis of the piston, and also angularly around said pistonaxis, allowing the magnets to be linearly displaced within the spacebetween the laminations of the motor, without touching said laminations.

In order to comply with the objects cited above, the present inventionprovides a mounting arrangement for a resonant spring in a linear motorcompressor of the type which comprises, in the interior of a shell: ablock defining a cylinder; a movable assembly formed by a pistonreciprocating in the cylinder, an actuating means and a rod coupling thepiston to the actuating means; and a resonant spring having a first anda second end portion which are disposed according to a diametricaldirection and attached, respectively, to the movable assembly, in acoaxial manner, by a first fixation means and, to the block, by a secondfixation means.

It should be noted that, due to the manufacturing process of theresonant spring, its diametrical end portions are not mandatorilyparallel to one another, since it is possible for an end portion to forman acute angle with the other.

According to the invention, the second fixation means is attached, withan adjustable relative positioning, to the block and to the second endportion of the resonant spring, so as to affix said second end portionto the block, in a position defined along the displacement of theresonant spring, in relation to the block, in three directionsorthogonal to each other and defined by the direction of the axis of theresonant spring, by the diametrical direction of said second endportion, and by the diametrical direction orthogonal to said two firstdirections, and also along the angular displacement of the second endportion of the resonant spring around said three directions orthogonalto each other.

Considering the previous fixation of the resonant spring to thecompression movable assembly, in a condition in which the axes of thetwo parts are coaxially maintained, the construction proposed for themounting arrangement, particularly for the second fixation means, allowsmaking the necessary alignment and axial positioning of the resonantassembly in relation to the cylinder of the compressor and to the motor,during the mounting of the latter.

The invention further provides a simplified construction for the firstfixation means, which allows the first end portion of the resonantspring to be attached to the compression movable assembly, in a positiondefined along its relative displacement in the diametrical direction ofsaid spring first end portion and around said direction, facilitatingthe coaxial alignment of the resonant spring with the compressionmovable assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below, with reference to the encloseddrawings, given by way of example of ways of carrying out the inventionand in which:

FIG. 1 represents a schematic and simplified longitudinal section viewof a compressor driven by a linear motor and having a resonant springmounted to the parts of assembly compressor and of non-resonantassembly, according to a prior art arrangement;

FIG. 2 represents a schematic and simplified longitudinal section viewof a compressor of the type showed in FIG. 1, deprived of the shell butcontaining the mounting arrangement of the present invention;

FIG. 3 represents a view similar to that of FIG. 2, but with thelongitudinal section plane being offset by 90 degrees in relation tothat of FIG. 2;

FIG. 4 represents a perspective view of part of the compressor showed inFIGS. 2 and 3, illustrating the resonant spring with its first endportion mounted to the first fixation means carried by the movableassembly;

FIG. 5 represents a perspective view of other part of the compressorshowed in FIGS. 2 and 3, illustrating the resonant spring with itssecond end portion affixed to the second fixation means already mountedto the block; and

FIGS. 6A, 6B and 6C represent perspective views of the differentcomponent parts of the second fixation means illustrated in FIGS. 2, 3and 5.

DETAILED DESCRIPTION OF THE INVENTION

As already mentioned, the mounting arrangement for a resonant spring ofthe present invention will be described for a construction ofrefrigeration compressor driven by a linear motor.

As illustrated in FIG. 2, the refrigeration compressor to which isapplied the mounting arrangement for a resonant spring of the presentinvention comprises, in the interior of a generally hermetic shell 1,the same basic components described at the introduction of the presentspecification for the linear motor compressor illustrated in FIG. 1,said common components being defined by the same reference numbers.

According to the illustrated construction, the resonant spring 50presents a helical configuration formed by two interposed spring wires,with the same diameter and having their adjacent end portions coaxial toeach other and disposed according to a diametrical direction orthogonalto the axis of the resonant spring 50, so as to define, jointly, thefirst and the second end portion 50 a, 50 b of the resonant spring 50.As previously mentioned, the two end portions 50 a, 50 b of the resonantspring 50 are not mandatorily parallel to one another, althoughmaintaining a diametrical positioning in relation to the resonant spring50.

According to the construction of the invention illustrated in FIGS. 2 to6C, the first fixation means MF1 comprises two bearing portions 60,opposite to one another and each provided with a recess 61 configured tooperate as a concave cradle, generally with a semi-circular profile, inthe interior of which is partially housed a respective extension of thefirst end portion 50 a of the resonant spring 50, said end portion beingdefined, in the illustrated construction, by the coaxial and adjacentends of the two spring wires.

It should be understood that the resonant spring 50 can have one or bothend portions 50 a, 50 b defined in an open manner, that is, by twospring wire coaxial extensions, or in a closed manner, with therespective spring wire coaxial extensions joined to each other by anycoupling means.

The two bearing portions 60 are configured to embrace and secure,therebetween, the first end portion 50 a of the resonant spring 50.

The two bearing portions 60 are incorporated to the actuating means 40and associated with at least one tightening means 62, for example ascrew, capable of moving and pressing one bearing portion against theother, one in relation to the other, by actuation of at least onetightening means 62 around the first end portion 50 a of the resonantspring 50, retaining said first end portion 50 a in the interior of thetwo mutually confronting recesses 61 of the two bearing portions 60. Inthe illustrated construction, the two bearing portions 60 areincorporated, in a single piece, to the actuating means 40 whichcomprises a frame 42 in the form of a nipper with two arms 43, eachhaving a base end 43 a attached to the other arm 43 and a free end 43 bwhich carries a respective bearing portion 60.

Each of the bearing portions 60 presents a hole 63, displaced inrelation to the adjacent recess 61 and constructed to receive thetightening means 62 in the form of a screw, and one of the holes 63 canbe internally threaded. The holes 63 of the bearing portions 60 aredisposed according to the same axis orthogonal to the axis of the recess61.

It should be understood that the two bearing portions 60 can beincorporated to the actuating means 40 in different manners, providedthat they can be selectively displaced for allowing pressing one againstthe other around the first end portion 50 a of the resonant spring 50,so as to affix the latter to the movable assembly. As illustrated inFIGS. 2, 3 and 4, the piston 20 is coaxially coupled, by the rod 30, tothe end of the frame 42, in which said two arms 43 of the latter areattached to each other.

Also according to the type of construction illustrated in the drawings,the frame 42 of the actuating means 40 carries the magnets 41 whichpresent the form of permanent magnets.

The construction proposed for the first fixation means MF1 allows thetwo bearing portions 60 to be defined in the frame 42 of the actuatingmeans 40, considerably simplifying the formation of the first fixationmeans MF1 and permitting the first end portion 50 a of the resonantspring 50 to be displaced, linearly, through the interior of the twobearing portions 60, before the final tightening of the latter,according to the diametrical direction of the axis of said first endportion 50 a, as well as angularly, around said diametrical axis. Thus,the positioning of the first end portion 50 a of the resonant spring 50can be linearly and angularly adjusted during the mounting of themovable assembly, before the final compression of the tightening means62, allowing easily obtaining the desired coaxial fixation of theresonant spring 50 to the actuating means 40, that is, to thecompression movable assembly. It should be understood that the resonantspring 50 is constructed to have its end portions 50 a and 50 bdiametrically and centrally positioned in relation to the axis of theresonant spring 50, but not necessarily parallel to one another.

In the preferred illustrated construction, the first and second endportion 50 a, 50 b of the resonant spring 50 are disposed coplanar toeach other and according to directions orthogonal to the axis of theresonant spring 50. In this case, the bearing portions 60 have the axesof the recesses 61 also disposed orthogonally to the axis of theresonant spring 50, allowing that the linear adjustment of thepositioning of the first end portion 50 a of the spring be madeaccording to a direction orthogonal to the axis of the resonant spring50, and that the angular adjustment of said first end portion 50 a bemade by angularly displacing the resonant spring 50 around the axis ofsaid first end portion 50 a.

The actuating means 40 can have its frame 42 in the form of a nipperconstructed in any adequate material such as, for example, cast aluminumalloy.

Further according to the invention, the second fixation means MF2comprises a base body 70, an intermediate body 80 and a top body 90,coupling the second end portion 50 b of the resonant spring 50 to theblock 10 of the compressor and which can be constructed in any adequatematerial such as, for example, steel metal alloys or sintered material.

The base body 70 is dimensioned to have two opposite end faces 70 ahoused between the free ends of two longitudinal projections 15 of theblock 10, which are diametrically opposite in relation to the contour ofthe cylinder 12. The free end of each longitudinal projection 15 of theblock 10 is provided with a longitudinal slot 16, preferably with anopen end, through which is attached a screw 17 whose body is screwed inthe interior of a respective hole 71 provided in a confronting end face70 a of the base body 70, which also presents a front face 70 b.

With the construction cited above, the base body 70 presents two holes71 opposite and coaxial to each other, each receiving and retaining arespective screw 17 mounted through the longitudinal slot 16 of arespective longitudinal projection 15 of the block 10. It should beunderstood that the holes 71 can be provided with an inner thread, toretain the threaded body of a respective screw 17, or be onlydimensioned for housing the body of a single screw disposed through saidholes and associated with a tightening nut.

Thus, the base body 70 can be displaced, linearly, in the direction ofthe longitudinal axis of the resonant spring 50 and, angularly, aroundthe common axis of the two threaded holes 71, which axis is disposedaccording to a direction simultaneously orthogonal to the axis of theresonant spring 50 and to the axis of the second end portion 50 b of thelatter. This construction allows carrying out the two positioningadjustments. (longitudinal linear and angular) of the base body 70before the final tightening of the screws 17 to immobilize the base body70 in the block 10.

In the illustrated construction, the base body 70 further incorporates,in its front face 70 b, a spacer 75 which projects forwards by apredetermined extension, as described ahead.

The intermediate body 80 presents a rear face 80 a, to be seated againstthe front face 70 b of the base body 70, and a front face 80 b.

The rear face 80 a can incorporate an orthogonal projection 81,generally in the form of a cylindrical pin, positioned so as to bemaintained coaxial or approximately coaxial to the axis of thecompression movable assembly, the orthogonal projection 81 beingdimensioned to be fitted and guided in the interior of an oblong recess72 provided in the front face 70 b of the base body 70. The oblongrecess 72 has its longitudinal axis parallel to the common axis of theholes 71. It should be understood that the positions of the orthogonalprojection 81 and of the oblong recess 72, in case these elements areeffectively provided, can be inverted, that is, the orthogonalprojection 81 being incorporated to the front face 70 b of the base bodyand the oblong recess being provided in the rear face 80 a of theintermediate body 80.

This construction allows the intermediate body 80 to be linearlydisplaced along the front face 70 b of the base body 70, guided by thelatter, in the direction of the common axis of the holes 71, that is, ina direction orthogonal to the axis of the resonant spring 50 and to thediametrical direction of the second end portion 50 b of the resonantspring 50.

The intermediate body 80 can be also rotated, together with itsorthogonal projection 81, around the axis of the latter, that is, arounda direction coincident with or parallel to the axis of the compressionmovable assembly. However, this construction does not allow theintermediate body 80 to be linearly displaced in relation to the basebody 70, according to a diametrical direction orthogonal to thelongitudinal axis of the oblong recess 72, that is, according to thediametrical direction of the second end portion 50 b of the resonantspring 50. The intermediate body 80 further presents, along the wholewidth of its front face 80 b, a recess 82 defining a concave cradle,generally with a semi-circular profile, or in any other shape compatiblewith the cross-sectional contour of the spring wire, as for example in aV-shape, having its axis orthogonal to the axis of the holes 71 of thebase body 70 and to the axis of the resonant spring 50. The recess 82 isdimensioned to operate as a cradle in which is seated an extension ofthe second end portion 50 b of the resonant spring 50.

Although the figures of the drawings do not illustrate any otherconstruction for the base body 70 and for the intermediate body 80, itshould be understood that the latter can be constructed without theorthogonal projection 81, in which case the oblong recess 72 issuppressed from the base body 70. In this case, instead of the secondend portion 50 b of the resonant spring 50 sliding in the recess 82 ofthe intermediate body 80, it is the latter which slides on the base body70, according to a diametrical direction coincident with that of thesecond end portion 50 b of the resonant spring 50.

The top body 90 has the function of pressing the second end portion 50 bof the resonant spring 50 against the recess 82 of the intermediate body80, as well as the latter against the front face 70 b of the base body70. For this purpose, the top body 90 is provided with at least twothrough holes 91, joining a rear face 90 a with a front face 90 b ofsaid top body 90 and which are axially aligned to respective threadedholes 73 provided in the base body 70 from its front face 70 b. Eachthrough hole 91 receives a screw 92 which is affixed in the interior ofa respective threaded hole 73 of the base body 70, allowing the top body90 to be pulled against the base body 70, compressing the second endportion 50 b of the resonant spring 50 against the intermediate body 80and the latter against the base body 70. It should be noted that theintermediate body 80 is dimensioned to be positioned between the screws92, thus being compressed between the base body 70 and the top body 90.The spacer 75 which, in the illustrated embodiment, is frontallyincorporated to the base body 70, allows the adjacent screw 92 to betightened until the spacer 75 actuates against the rear face 90 a of thetop body 90. Thus, the other screw 92 can be tightened to provide thefinal retention of the second end portion 50 b of the resonant spring50, after correctly adjusting the alignment of the resonant assembly inrelation to the cylinder 12. Nevertheless, it should be understood thatthe spacer 75 can be optionally incorporated, in a single piece, to therear face 90 a of the top body 90.

With the construction proposed for the second fixation means MF2, it ispossible to submit the second end portion 50 b of the resonant spring 50to the following positioning adjustments, before the final tightening ofthe screws 17 of the block 10 and of the screws 92 of the top body 90:

a—axial displacement of the base body 70 (and of the assembly formed bythe intermediate body 80, the top body 90, the resonant spring 50 andthe compression movable assembly 20,30,40) in relation to the block 10;

b—angular displacement of the base body 70 (and of the second endportion of the resonant spring 50) around an axis coincident with thatof the holes 31 of said body and simultaneously orthogonal to the axisof the resonant spring 50 and to the axis of the second end portion 50 bof the latter;

c—linear displacement of the intermediate body 80 (and of the second endportion 50 b of the resonant spring 50) in a direction orthogonal to theaxis of the resonant spring 50 and parallel to the axis of the holes 71of the base body 70;

d—angular displacement (rotation) of the intermediate body 80 (and ofthe resonant spring 50 and of the compression movable assembly 20,30,40)around the axis of the orthogonal projection 81, around the axis of thelatter, that is, around a direction coincident with or parallel to theaxis of the spring and of the compression movable assembly;

e—linear displacement of the second end portion 50 b of the resonantspring 50 in the interior of the recess 82 of the intermediate body 80,in the direction of said spring second end portion, upon the existenceof the orthogonal projection 81 of the intermediate body 80 fitted inthe oblong recess 72 of the base body 70; and

f—rotational displacement of the second end portion 50 b of the resonantspring 50 in the interior of the recess 82 of the intermediate body 80,around the axis of said second end portion 50 b, which axis isorthogonal to the axis of the resonant spring 50.

It should be noted that, when the orthogonal projection and the oblongrecess 72 are suppressed from the intermediate body 80 and base body 70,respectively, the positioning adjustment described above in item “e” iscarried out by the intermediate body 80 sliding on the base body 70,according to a diametrical direction coincident with that of the secondend portion 50 b of the resonant spring 50. In this case, it is not thesecond end portion 50 b of the resonant spring 50 which slides in therecess 82 of the intermediate body 80, but rather the intermediate body80 on the base body 70.

The mounting arrangement of the present invention allows that, beforethe final fixation of the resonant spring 50 to the movable assembly 20,30, 40 and to the block 10, the resonant spring 50 can have: its firstend portion 50 a moved transversally to the axis of the spring andangularly around the axis of the first end portion 50 a; and also itssecond end portion 50 b moved in the direction of the axis of theresonant spring 50, in two diametrical directions, orthogonal to oneanother and in relation to the spring axis, as well as angularly aroundthree axes orthogonal to one another, one of them being a diametricalaxis of the resonant spring 50, coincident with the second end portion50 b of the latter.

This possibility of providing the mounting adjustment of rigidcomponents, which are not subject to the thermo-chemical deterioration,allows providing a concentric mounting of the piston 20 in the interiorof the cylinder 12 and of the magnets in relation to the motor M, saidconcentricity being maintained during the operation of the compressor,minimizing or even preventing impacts of the piston 20 against the innersurface of the cylinder 12. The present mounting arrangement also allowsadjusting the relative axial positioning of the piston 20 in relation tothe top of the cylinder 12, so as to guarantee a volumetric displacementand refrigeration capacity previously projected for the compressoroperation.

The mounting arrangement of the present invention does not require veryprecise tolerances of the components, both in the direction of the axisof the cylinder 12 and of the resonant spring 50, and in directionsorthogonal to one another and to said axis, without compromising theconcentric positioning of the movable assembly in relation to thecylinder axis, and the distance from the top of the piston 20 to thevalve plate 14 in order to define the displaced volume and thecorresponding refrigeration capacity of the compressor.

1. A mounting arrangement for a resonant spring in a linear motorcompressor of the type which comprises, in the interior of a shell: ablock defining a cylinder; a movable assembly formed by a pistonreciprocating in the cylinder, an actuating means and a rod coupling thepiston to the actuating means; and a resonant spring having a first anda second end portion which are disposed according to a diametricaldirection and attached, respectively, to the movable assembly, in acoaxial manner, by a first fixation means (MF1) and, to the block, by asecond fixation means (MF2), characterized in that the second fixationmeans (MF2) is affixed, with an adjustable relative positioning, to theblock and to the second end portion of the resonant spring, so as toaffix said second end portion to the block, in a position defined alongthe displacement of the resonant spring in relation to the block, inthree directions orthogonal to one another and defined by the directionof the axis of the resonant spring, by the diametrical direction of saidsecond end portion, and by the diametrical direction orthogonal to saidtwo first directions, and also along the angular displacement of thesecond end portion of the resonant spring around said three directionsorthogonal to one another.
 2. The mounting arrangement, as set forth inclaim 1, characterized in that the second fixation means (MF2) isaffixed to the block in a position defined along a linear displacementand an angular displacement of said second fixation means (MF2) inrelation to the block respectively, in the direction of the axis of theresonant spring and around an axis diametrical to the resonant springand orthogonal to the axis of the latter and to the diametricaldirection of said second end portion, the latter being affixed to thesecond fixation means (MF2) in a position defined along a lineardisplacement of the resonant spring in the diametrical direction of saidsecond end portion and in a diametrical direction orthogonal to thedirection of said second end portion, and along an angular displacementof the resonant spring around said diametrical direction of said secondend portion and around the direction of the axis of the resonant spring.3. The mounting arrangement, as set forth in claim 2, characterized inthat the second fixation means (MF2) comprises: a base body attached tothe block in a position defined along its linear displacement and alongits angular displacement, respectively, in the direction of the axis ofthe resonant spring and around an axis diametrical to the resonantspring and orthogonal to the diametrical direction of said second endportion; an intermediate body seated against the base body, so as to bedisplaced, linearly, in a diametrical direction orthogonal to thedirection of said second end portion and, angularly, around thedirection of the axis of the resonant spring, said intermediate bodypresenting a face opposite to the face to be seated on the base body, onwhich is seated the second end portion of the resonant spring; and a topbody attached to the base body, so as to press the second end portion ofthe resonant spring against said opposite face of the intermediate bodyand the latter against the base body.
 4. The mounting arrangement, asset forth in claim 3, characterized in that said opposite face of theintermediate body is provided with a recess in which is seated thesecond end portion of the resonant spring, said top body being attachedto the base body, so as to press the second end portion of the resonantspring in the recess of the intermediate body.
 5. The mountingarrangement, as set forth in claim 3, characterized in that the blockpresents two longitudinal projections diametrically opposite in relationto the cylinder and each presenting a free end provided with alongitudinal slot, said base body presenting opposite end faces and twocoaxial holes, each being provided from an end face, to receive andretain a screw mounted through the slot of a longitudinal projection ofthe block.
 6. The mounting arrangement, as set forth in claim 5,characterized in that the intermediate body presents a rear face, to beseated against the front face of the base body, and a front face, one ofthe parts of rear face of the intermediate body and of front face of thebase body incorporating an orthogonal projection, in the form of acylindrical pin, to be fitted and guided in the interior of an oblongrecess provided in one of the parts defined by the front face of thebase body and by the rear face of the intermediate body, said oblongrecess having its longitudinal axis parallel to the common axis of theholes and orthogonal to the diametrical direction of the second endportion of the resonant spring.
 7. The mounting arrangement, as setforth in claim 6, characterized in that the orthogonal projection iscoaxial or approximately coaxial to the axis of the compression movableassembly.
 8. The mounting arrangement, as set forth in claim 6,characterized in that the top body presents a rear face and a front facejoined to each other by at least two through holes axially aligned torespective threaded holes provided in the base body from its front face,each through hole receiving a screw to be affixed in the interior of arespective threaded hole of the base body.
 9. The mounting arrangement,as set forth in claim 8, characterized in that one of the parts definedby the base body and top body incorporates, in its face turned to theother of said parts, a spacer which projects in direction to the otherpart, to be seated thereon upon tightening of the adjacent screw. 10.The mounting arrangement, as set forth in claim 1, characterized in thatthe first fixation means (MF1) comprises two bearing portions oppositeto each other and each provided with a recess in the form of a concavecradle, in which is partially housed a respective extension of the firstend portion of the resonant spring, said bearing portions beingincorporated to the actuating means and associated with at least onetightening means, capable of pressing one bearing portion against theother, around the first end portion of the resonant spring.
 11. Themounting arrangement, as set forth in claim 10, characterized in thatthe actuating means comprises a frame in the form of a nipper with twoarms, each arm having a base end affixed to the other arm and a free endwhich carries, in a single piece, a respective bearing portion.
 12. Themounting arrangement, as set forth in claim 11, characterized in thateach of the bearing portions presents a hole displaced in relation tothe adjacent recess and constructed to receive the tightening means inthe form of a screw, said holes being disposed according to the sameaxis orthogonal to the axis of the recess.
 13. The mounting arrangement,as set forth in claim 12, characterized in that the resonant spring isformed by two interposed spring wires, with the same diameter and havingtheir adjacent end portions coaxial to each other and disposed accordingto a diametrical direction orthogonal to the axis of the resonantspring, so as to define, jointly, the first and the second end portionof the resonant spring.